Redox additive electrolyte assisted promising pseudocapacitance from strictly 1D and 2D blended structures of MnO2/rGO

Abstract

A promising sustainable energy storage characteristic is achieved in redox additive electrolyte by developing strict blend of one dimensional (1D) and two dimensional (2D) structures. Hydrothermal reaction is followed to obtain the desired morphology. Two dimensional (2D) reduced graphene oxide (rGO) is added into the redox reaction between potassium permanganate and sodium nitrite to obtain nanocomposite comprising 1D and 2D blended structures of MnO 2 /rGO. Their structures and morphologies are studied by XRD, Raman and HRTEM analyses, respectively. The pseudocapacitive behaviour is studied in a redox additive electrolyte comprising KOH and K 3 Fe(CN) 6 . The effect of electrolytic concentration was studied by varying the concentration of K 3 Fe(CN) 6 . The specific capacity is considerably enhanced up to 1741 F/g, 8.75 A/g with increase in concentration of K 3 Fe(CN) 6 . The role of redox couple [Fe(CN) 6 ] 3− /[Fe(CN) 6 ] 4− played a key role in adding the charge movement across the electrode which tuned well with the manganese ions to obtain one of the most promising pseudocapacitances from the developed 1D and 2D blended structures of MnO 2 /rGO. For in-depth analysis of Fe ions movement, a symmetric supercapacitor cell is constructed to achieve a commendable specific capacitance of 216 F/g at 3.75 A/g. Prolong cycling hinted decreasing electrolytic interfacial layers resulting in fast reversible kinetics of Fe(III) ↔ Fe(II) ions to achieve astonishing capacity retention of 127% after 3000 cycles. • 1D MnO 2 is easily blended with fine nanosheets of rGO as a pseudocapacitor electrode. • Promising pseudocapacitance of 216 F/g at 3.75 A/g in a two-electrode system is achieved. • Pseudocapacitive behaviour is studied under redox additive electrolyte, K 3 Fe(CN) 6 .